From 7e4d1176634203cb31b6e4eb449a1b18729dc5a9 Mon Sep 17 00:00:00 2001
From: Naushir Patuck <naush@raspberrypi.com>
Date: Wed, 1 Apr 2020 08:46:29 +0100
Subject: [PATCH] media: uapi: v4l2-core: Add sensor ancillary data
 V4L2 foucc type.

Add V4L2_META_FMT_SENSOR_DATA format 4CC.

This new format will be used by the BCM2835 Unicam device to return
out camera sensor embedded data.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
---
 .../userspace-api/media/v4l/meta-formats.rst  |  1 +
 .../media/v4l/pixfmt-meta-sensor-data.rst     | 32 +++++++++++++++++++
 drivers/media/v4l2-core/v4l2-ioctl.c          |  1 +
 include/uapi/linux/videodev2.h                |  1 +
 4 files changed, 35 insertions(+)
 create mode 100644 Documentation/userspace-api/media/v4l/pixfmt-meta-sensor-data.rst

--- a/Documentation/userspace-api/media/v4l/meta-formats.rst
+++ b/Documentation/userspace-api/media/v4l/meta-formats.rst
@@ -15,6 +15,7 @@ These formats are used for the :ref:`met
     pixfmt-meta-d4xx
     pixfmt-meta-intel-ipu3
     pixfmt-meta-rkisp1
+    pixfmt-meta-sensor-data
     pixfmt-meta-uvc
     pixfmt-meta-vsp1-hgo
     pixfmt-meta-vsp1-hgt
--- /dev/null
+++ b/Documentation/userspace-api/media/v4l/pixfmt-meta-sensor-data.rst
@@ -0,0 +1,32 @@
+.. Permission is granted to copy, distribute and/or modify this
+.. document under the terms of the GNU Free Documentation License,
+.. Version 1.1 or any later version published by the Free Software
+.. Foundation, with no Invariant Sections, no Front-Cover Texts
+.. and no Back-Cover Texts. A copy of the license is included at
+.. Documentation/media/uapi/fdl-appendix.rst.
+..
+.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
+
+.. _v4l2-meta-fmt-sensor-data:
+
+***********************************
+V4L2_META_FMT_SENSOR_DATA  ('SENS')
+***********************************
+
+Sensor Ancillary Metadata
+
+Description
+===========
+
+This format describes ancillary data generated by a camera sensor and
+transmitted over a stream on the camera bus. Sensor vendors generally have their
+own custom format for this ancillary data. Some vendors follow a generic
+CSI-2/SMIA embedded data format as described in the `CSI-2 specification.
+<https://mipi.org/specifications/csi-2>`_
+
+The size of the embedded buffer is defined as a single line with a pixel width
+width specified in bytes. This is obtained by a call to the
+:c:type:`VIDIOC_SUBDEV_G_FMT` ioctl on the sensor subdevice where the ``pad``
+field in :c:type:`v4l2_subdev_format` is set to 1.  Note that this size is fixed
+and cannot be modified with a call to :c:type:`VIDIOC_SUBDEV_S_FMT`.
+
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -1448,6 +1448,7 @@ static void v4l_fill_fmtdesc(struct v4l2
 	case V4L2_META_FMT_RK_ISP1_STAT_3A:	descr = "Rockchip ISP1 3A Statistics"; break;
 	case V4L2_PIX_FMT_NV12M_8L128:	descr = "NV12M (8x128 Linear)"; break;
 	case V4L2_PIX_FMT_NV12M_10BE_8L128:	descr = "10-bit NV12M (8x128 Linear, BE)"; break;
+	case V4L2_META_FMT_SENSOR_DATA:	descr = "Sensor Ancillary Metadata"; break;
 
 	default:
 		/* Compressed formats */
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -813,6 +813,7 @@ struct v4l2_pix_format {
 #define V4L2_META_FMT_UVC         v4l2_fourcc('U', 'V', 'C', 'H') /* UVC Payload Header metadata */
 #define V4L2_META_FMT_D4XX        v4l2_fourcc('D', '4', 'X', 'X') /* D4XX Payload Header metadata */
 #define V4L2_META_FMT_VIVID	  v4l2_fourcc('V', 'I', 'V', 'D') /* Vivid Metadata */
+#define V4L2_META_FMT_SENSOR_DATA v4l2_fourcc('S', 'E', 'N', 'S') /* Sensor Ancillary metadata */
 
 /* Vendor specific - used for RK_ISP1 camera sub-system */
 #define V4L2_META_FMT_RK_ISP1_PARAMS	v4l2_fourcc('R', 'K', '1', 'P') /* Rockchip ISP1 3A Parameters */
